Data Analysis
The analysis was performed on the basis of intention to treat and
included all participants. Outcomes were pooled using mean differences
(MD) (inverse variance method), standardized mean differences (SMD) for
similar outcomes measured in different scales, and Mantel-Haenszel risk
ratios (RR). When significant data was reported only in median and IQR,
mean and SD were estimated according to the
literature16, and the estimation was pooled in the
meta-analysis; all estimated data will be properly identified. Estimate
precision was quantified by 95% confidence intervals (CI).
Heterogeneity was measured by the I2 test (≤25%
absence of bias; 26 to 39% unimportant; 40% to 60% moderate; and 60%
to 100% substantial bias)17. A fixed-effects model
was used when there was no evidence of significant heterogeneity in the
analysis (I2 <40%); if significant
heterogeneity was found, a random-effects model was
used18,19. A priori subgroup analyses included:
setting (ED vs. hospitalized), age (preschooler vs. school-age),
acute asthma severity score, doses
of ICS, type of SC, and sponsored (pharmaceutical industry vs.
independent). The meta-analysis was performed with Review Manager 5.3.5
software (Cochrane IMS, 2014).